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PubMed1997

The in ovo carcinogenicity assay (IOCA): a review of an experimental approach for research on carcinogenesis and carcinogenicity testing.

Up to now, the carcinogenicity of a substance, i.e., its cancer-causing effect, has been usually determined with the help of extensive animal testing. The in ovo carcinogenicity assay (IOCA) has been suggested as a rapid and inexpensive, non-animal, method for carcinogenicity testing and for experimental studies on mechanisms of carcinogenesis. The substance to be tested is injected into a fertilized ovum. No later than four days before the hatching date, the embryos are released, and the liver is removed for identifying the effect of hepatocarcinogens. Histological, cytological and molecular biological alterations of the embryonic liver have been induced with a variety of chemical carcinogens. After sufficiently high doses of hepatocarcinogens, tubular structures predominate in the liver and replace the normal trabecular pattern. The cell and nuclear size of the hepatocytes in embryonic liver is severely increased after exposure to chemical carcinogens over a wide dose range including doses that fail to elicit cytotoxicity in the embryonic liver.

Animals↗
PubMed1991

Ultrasonographic patterns of ovarian activity during breastfeeding.

In this study, ultrasonography was used to detect follicular activity in lactating women, and these findings were related to the underlying hormonal profiles and to the mucus symptom. A number of different patterns of follicular development were seen before the women returned to normal fertile cycles during the period that was previously considered to be characterized by ovarian quiescence. Some of the transitory patterns of follicular activity were reflected in rising hormone levels and patterns of fertile mucus that were sometimes confusing for these lactating women who were using natural family planning.

Breast Feeding↗
PubMed1994

Measuring the effort levels of family planning programmes (profile of 30 programme effort scores, 1982 and 1989).

The chief results to emerge in this preliminary analysis are as follows: Stronger programmes are stronger on every score. Their overall superiority in the total score is not due to exceptional stress on any one feature, but rather to a substantial advantage score by score, across all 4 dimensions of effort. A further difference is that stronger programmes have more consistent values across the various scores, quite apart from their levels, whereas weaker programmes are erratic, displaying much greater variability around their own mean score than do the stronger programmes. The profiles themselves (apart from levels) have not changed from 1982 to 1989. Stronger programmes in 1989 show the same score patterns as did the smaller number of stronger programmes in 1982. This also holds true for weaker programmes: the profile of the weaker programmes in 1982 was duplicated in 1989, even though countries left that category and moved into the stronger group. The 19 countries that shifted to the higher category conformed to the profile of weaker countries in 1982 (though at a slightly higher level); but conformed to the profile of stronger countries in 1989 (though at a slightly lower level). Thus it is likely that maturing programmes tend to follow a special pattern of improvement: They improve differentially across the 30 scores. The prevalence of contraceptive use is closely associated with programme effort, but some programme features count more than others. The availability scores for contraceptive methods count most, and service and service-related efforts come next.(ABSTRACT TRUNCATED AT 250 WORDS)

Contraception Behavior↗
PubMed1995

Detection of anti-neutrophil cytoplasmic antibodies by immunoprecipitation.

Immunoprecipitation (IP) of radiolabeled PMN extracts was used as the gold standard for anti-proteinase 3 (PR-3) autoantibody detection to validate immunofluorescence (IF) and alpha granule (alpha) ELISA. A myeloperoxidase (MPO) ELISA was also used in parallel. We studied 48 patients with strictly defined vasculitic syndromes in the initial active phase of their disease. The 3 methods confirmed the high (> 90%) sensitivity and specificity of anti-PR-3 for patients with Wegener's granulomatosis (WG). Similarly, a high (86%) sensitivity of MPO-ELISA was found in microscopic polyarteritis as defined. Using alpha-ELISA, we could not improve the detection rate of anti-PR-3 obtained by IF-cANCA-pattern reading. Moreover, a small proportion (< 15%) of biopsy-proven WG patients had anti-MPO antibodies detected by IF, usually as pANCA but also, even if rarely, as bona fide cANCA (< 5%). Thus, IF would seem to be the most reliable screening method and alpha-ELISA should be used for confirmation. On the other hand, because MPO-ELISA detected twice as many anti-MPO positive sera as did pANCA pattern reading by IF, we suggest that in the clinical context of a vasculitis, MPO-ELISA should also be used as a screening test. Although IP is not designed for routine clinical use, it should be required when reporting the presence of anti-PR-3 in vasculitis-like diseases that are fertile grounds for false positive reactions.

Adult↗
PubMedDate not supplied

Exposure misclassification due to residential mobility during pregnancy in epidemiologic investigations of congenital malformations.

This study addressed the question of how maternal migration between conception and birth affects estimates of risk in studies of congenital malformations when movement is related to the exposure. For example, in studying the potential association between proximity to a chemical waste site and the occurrence of birth defects, incorrect inferences might be drawn if maternal residence at birth was used as a surrogate for exposure at conception in the case when a significant amount of media attention influenced some women to move away from the site after becoming pregnant. A simple statistical model is proposed that defines the distance to a fixed exposure point measured at birth as a function of the distance to the point measured at conception, the probability of movement, the direction of movement, and the distance moved. Bias is the difference between the expected results when distance is measured at birth versus conception. The amount of bias can be substantial for movement patterns that may be likely to occur. This simplified model was used in an effort to explore and better understand the relationships between maternal migration and risk.

Abnormalities, Drug-Induced↗
PubMed1992

A survey of contraceptive use and unplanned pregnancy in Perth, Western Australia.

Contraceptive use and unplanned pregnancy were studied in a stratified cluster sample of 1,511 couples with women aged 16 to 44 years resident in metropolitan Perth in 1988. Twenty-one couples were excluded from analysis owing to missing data. The proportion of couples using contraception was 76.8 per cent (1,144 of 1,490), and all but three of the remaining couples gave a reason for nonuse. Among users, surgical sterilisation made up 42.3 per cent (484 of 1,144) of all methods, with a slight predominance of tubal ligation over vasectomy. Oral contraceptives accounted for just over half of nonsurgical methods. Comparisons with a Victorian survey performed in 1978 suggested that surgical methods and condom use may have increased, whereas use of oral contraceptives and intrauterine devices may have fallen. Unplanned pregnancies conceived during the 12 months before the interview affected 3.4 per cent (51 of 1,490) of respondents. The incidence of unplanned pregnancy was four times higher in couples with inconsistent usage patterns of contraception.

Adolescent↗
PubMed2005

The variability in the interval between estrus and ovulation in cattle and its determinants.

Fertility of Holstein cows has been decreasing for years and, to a lesser extent, the fertility of heifers too but more recently. A hypothesis to explain this phenomenon may be that the chronology of events leading to ovulation is different for those animals bred nowadays when compared to what was reported previously; this would result in an inappropriate time of insemination. Therefore, two experiments were designed to investigate the relationships among estrus behavior, follicular growth, hormonal events and time of ovulation in Holstein cows and heifers. In the first experiment, the onset of estrus, follicular growth, patterns of estradiol-17beta, progesterone and LH, and the time of ovulation were studied in 12 cyclic Holstein heifers that had their estrus synchronized using the Crestar method; this was done twice, 3 weeks apart. The intervals between estrus and ovulation, estrus and the LH peak, and between the LH peak and ovulation were, respectively, 38.5 h +/-3.0, 9.1 +/- 2.0 and 29.4 h +/-1.5 (mean+/- S.E.M). The variation in the interval between estrus and the LH peak explained 80.6% of the variation in the interval between estrus and ovulation. The intervals between estrus and the LH peak, and estrus and ovulation were correlated with estradiol-17beta peak value (r=-0.423, P <0.04 and r=-0.467, P<0.02, respectively). Positive correlation coefficients for the number of follicle larger than 5 mm, and negative correlation coefficients for the size of the preovulatory follicle with the intervals between estrus and LH peak, LH peak and ovulation, and estrus and ovulation suggest an ovarian control of these intervals. In respect to its role to explain the variation in the interval between estrus and ovulation, the variation in the interval between estrus and the LH peak was evaluated further in a second set of experiments utilizing 12 pubertal Holstein heifers and 35 Holstein cows. The duration of the interval between the beginning of estrus and the LH peak was longer in heifers than in cows (4.15 h versus -1.0 h; P <0.002); the variation for this interval was higher in cows than in heifers (S.E.M.= 1.2 h versus 0.8 h; P=0.01). According to the results of these studies it can be proposed that estradiol and other product(s) of ovarian origin regulate not only the duration of intervals between the onset of estrus and the LH surge but also between the LH surge and ovulation. From the results obtained in the first experiment, it may be postulated that differences observed between cows and heifers for the duration of the interval between onset of estrus and the LH surge as well as for the variation of this interval would be observed also for the interval between the onset of estrus and ovulation. Therefore, on a practical point of view, the long interval between the onset of estrus and ovulation and the high variation of this interval, especially in cows, may be a source of low fertility and should be considered when analysing reproductive disorders.

Animals↗
PubMed2005

Uterine effects of metformin administration in anovulatory women with polycystic ovary syndrome.

BACKGROUND: Metformin has been shown to improve fertility in anovulatory patients with polycystic ovary syndrome (PCOS), inducing not only a high ovulation and pregnancy rate but also reducing the incidence of miscarriages. The aim of the present study was to evaluate the uterine effects of metformin in patients with PCOS who ovulated under metformin. METHODS: Thirty-seven non-obese primary infertile anovulatory patients with PCOS and another 30 age- and body mass index-matched healthy women (control group) were studied. PCOS patients were treated with metformin (850 mg twice daily) for 6 months, whereas the control group did not receive any treatment. In these PCOS patients who ovulated whilst under metformin treatment (PCOS group) and in controls, uterine, sub-endometrial and endometrial blood flow, and endometrial thickness and pattern were evaluated using serial ultrasonographic assessments. RESULTS: Before treatment, uterine, sub-endometrial and endometrial blood flows were significantly lower in patients with PCOS than in the control group. All indexes of uterine vascularization were significantly improved in the PCOS group with metformin treatment and were not different from the controls. Nor was any difference in endometrial thickness and pattern detected between PCOS and control groups. After grouping the data of PCOS patients who ovulated under metformin for cycles with favourable/unfavourable reproductive outcome, no difference in any parameter was observed. CONCLUSIONS: Metformin improves all surrogate markers of endometrial receptivity in PCOS patients, without difference between patients who had favourable or unfavourable reproductive outcome.

Adult↗
PubMed1991

Immunoelectron microscopic localization of small nuclear ribonucleoproteins during bovine early embryogenesis.

Small nuclear ribonucleoproteins (snRNPs) were localized using human autoimmune or monoclonal anti-snRNP antibodies and ultrastructural immunocytochemistry in early preimplantation bovine embryos before and at transcription onset. Bovine cleavage stages up to 16-cell embryos were obtained either by culture of in vitro-fertilized ovarian oocytes or by isolation at slaughter of embryos fertilized and developed in vivo. Before transcription onset, up to the four-cell stage, diffuse labeling of nucleoplasm was detected, whereas cytoplasm labeling remained low. At the transcription onset, labeling of all eight-cell embryo nuclei was markedly concentrated at the borderline of already formed, condensed chromatin aggregates, where it was associated mainly with perichromatin fibrils. The condensed chromatin blocks revealed by several different staining methods were more prominent than is the case in most somatic cells. The degree of chromatin condensation and the pattern of its distribution differed between in vivo- and in vitro-produced eight-cell embryos: the in vitro embryos showed a higher degree of chromatin condensation and a peripheral distribution of chromatin blocks. A relation of this observation to the developmental potential of cow embryos is suggested. In two- and four-cell embryos, intensive labeling was seen in interchromatin granules, which, in their turn, were often seen in close proximity to the nucleolus precursor bodies, or in the four-cell stage were interconnected to them. No labeling was ever seen, using antibodies specific for the snRNP Sm antigen, in nucleolar precursor bodies during embryonic nucleologenesis nor in the resulting nucleoli. There was some incidental labeling of the large central vacuole appearing at the beginning of the nucleolus precursor body transformation, testifying the nucleoplasmic origin of this entity.

Animals↗
PubMed1993

Fertile asymmetric somatic hybrids between Lycopersicon esculentum Mill. and Lycopersicon peruvianum var. dentatum Dun.

Thirteen nuclear asymmetric hybrids were regenerated under selective conditions following fusion of chlorophyll-deficient protoplasts from cultivated tomato (Lycopersicon esculentum Mill.) and gamma-irradiated protoplasts from the wild species Lycopersicon peruvianum var. dentatum Dun. All hybrid plants were classified as being asymmetric based on morphological traits, chromosome numbers and isozyme patterns. The majority of the hybrids inherited Lycopersicon peruvianum var. dentatum chloroplasts. Mitochondrial DNA analysis revealed mixed mitochondrial populations deriving from both parents in some of the hybrids and rearranged mitochondrial DNA in others. The asymmetric hybrids express some morphological traits that are not found in either of the parental species. Fertile F1 plants were obtained after self-pollination of the asymmetric hybrids in four cases. The results obtained confirm the potential of asymmetric hybridization as a new source of genetic variation, and as a method for transferring of a part of genetic material from donor to recipient, and demonstrate that it is possible to produce fertile somatic hybrids by this technique.

Acid Phosphatase↗
PubMed1999

Ontogeny of expression of a receptor for platelet-activating factor in mouse preimplantation embryos and the effects of fertilization and culture in vitro on its expression.

Platelet-activating factor (PAF; 1-o-alkyl-2-acetyl-sn-glycero-3-phosphocholine) is a potent ether phospholipid. It is one of the preimplantation embryo's autocrine growth/survival factors. It may act via a G protein-linked receptor on the embryo; however, the evidence for this is conflicting. The recent description of the intracellular form of the PAF:acetlyhydrolase enzyme as having structural homology with G proteins and Ras also suggests this as a potential intracellular receptor/transducer for PAF. This study used reverse transcription-polymerase chain reaction to examine the ontogeny of expression of the genes for these proteins in the oocyte and preimplantation-stage embryo. Transcripts for the G protein-linked PAF receptor were detected in the late 2-cell-stage embryo and in all stages from the 4-cell stage to blastocysts. They were also present in unfertilized oocytes and newly fertilized zygotes but only at relatively low levels. The incidence of expression was generally low and variable in late zygotes and early 2-cell embryos. Expression past the 2-cell stage was alpha-amanitin sensitive. The results indicated that mRNA for this receptor is a maternal transcript that was degraded during the zygote-2-cell stage. New expression of the receptor transcript required activation of the zygotic genome. Fertilization of embryos in vitro caused this transcript not to be expressed in the zygote. Culture of zygotes (irrespective of their method of fertilization) caused expression from the zygotic genome to be retarded by more than 24 h. This retardation did not occur if culture commenced at the 2-cell stage. The transcripts for the subunits of intracellular PAF:acetylhydrolase were not detected in oocytes or at any stage of embryo development examined, despite their being readily detected in control tissue. This study confirms the presence of the G protein-linked PAF receptor in the 2-cell embryo and describes for the first time its normal pattern of expression during early development. The adverse effects of in vitro fertilization (IVF) and embryo culture on the expression of this transcript may be a contributing factor for the poor viability of embryos produced in this manner. The reduced expression of PAF-receptor mRNA following IVF predicts that such embryos may have a deficiency in autocrine stimulation and also suggests that supplementation of growth media with exogenous PAF would be only partially beneficial. The effect of IVF and culture may also explain the conflicting literature.

Animals↗
PubMed2000

Clinical applications of serum placental protein 14 (PP14) measurement in the IVF-ET cycle.

OBJECTIVE: Placental protein 14 (PP14) is known to be one of the endometrial proteins that reflect endometrial functioning throughout the menstrual cycle. In this study, we examined PP14 as a marker for human endometrial receptivity in order to predict the outcome of in vitro fertilization and the embryo-transfer (IVF-ET) cycle. PATIENTS AND METHODS: The subjects were 72 women who had 96 IVF-ET cycles and who were examined at Tokyo Medical University Hospital during the period of January 1998 to June 1998 because of mechanical or unexplained infertility for a duration of at least 2 years. Serum samples were collected from all patients during treatment cycles, and serum PP14 concentrations were measured by a newly established enzyme-linked immunosorbent assay (ELISA). RESULTS: In the pregnant group, serum PP14 concentrations were markedly increased after ET, and a significant difference between the pregnant group and the nonpregnant group was observed 8 days following ET (p < 0.01). PP14 concentrations were higher in patients with endometria that exhibited homogenous patterns and that were more than 7 mm thicker than in other patients, as determined by ultrasound on the day of oocyte collection (p < 0.005). The pregnancy rates of patients with homogeneous patterns were lower than those of patients showing a trilaminar pattern. No pregnancies were observed when serum PP14 concentrations were greater than 6.85 U/l on the day of oocyte collection. CONCLUSION: PP14 might be a useful marker for human endometrial receptivity to predict the outcome of IVF-ET cycles.

Adult↗
PubMed1983

Location of specific messenger RNAs in Caenorhabditis elegans by cytological hybridization.

We have developed an autoradiographic technique for detecting specific Caenorhabditis elegans messenger RNA molecules in situ by hybridization of labeled, cloned DNA probes to fixed tissue sections and squashes of embryos and adults. We report analyses with probes of actin and collagen gene sequences from a C. elegans genomic clone library. Hybridization is RNase sensitive and tissue specific. In adults the actin probe, which recognizes cytoplasmic as well as muscle actin mRNA, hybridizes strongly to muscle and distal gonad (ovary), somewhat less strongly to maturing oocytes, and weakly to intestine. The collagen probe hybridizes weakly to distal gonad and intestine and very strongly to subcuticular tissues, in particular to the hypodermal cells and syncytial cytoplasm of the lateral hypodermal ridges, which are the sites of cuticle synthesis. In embryos, hybridization to squashes indicates that actin message is present at fertilization, decreases during early cleavage, and then increases again during morphogenesis. By contrast, collagen message is absent until the 100-cell stage and then increases rapidly during morphogenesis. The number of cells labeled is consistent with the view that the collagen probe hybridizes to hypodermal precursor cells. We estimate that our present methods can detect messages representing about 0.2% or more of the total mRNA population, and increases in this sensitivity should be possible. Therefore, the cytological hybridization technique should be useful for determining temporal and spatial patterns of specific mRNA distributions during development, at least for abundant and moderately abundant messages.

Actins↗